The lake carries three names, and each says something different. In Norwegian it is Ranseren. In Swedish it is Bije-Ransarn, and in Southern Sami, Bijjie Raentsere — both meaning the upper Ranseren, because there is a lower one. Follow the outflow east and it delivers into Ransarn proper, a far bigger lake in Vilhelmina Municipality, which is why this one has spent centuries being described in relation to it. The border cuts the lake unevenly: rather more than half of its roughly three square kilometres belongs to Hattfjelldal Municipality in Nordland, the rest to Västerbotten. It is a narrow thing, well under a kilometre wide along most of its length, draining a catchment of about ninety-five square kilometres of bare mountain.

About five hundred metres south of the border, on the Swedish side, stands a small Sami building used during the reindeer marking season. It is easy to miss and easy to underrate. Calf marking is the fixed point of the herding year: the herd is gathered in early summer, and each calf receives the pattern of cuts in its ear that identifies the family it belongs to. The work is done by hand, on foot, at whatever hour the animals cooperate, and it requires people to stay out on the fell for days. Southern Sami families have grazed these mountains for at least five centuries. A hut like this one is not a monument to that — it is working infrastructure, no more remarkable to the people who use it than a barn.

The Norwegian half of Ranseren falls inside Børgefjell National Park, established in 1963 and now covering 1,447 square kilometres across four municipalities and two counties. Børgefjell is deliberately undeveloped. There are no marked trails and no tourist cabins anywhere in it, which in a country as thoroughly hut-networked as Norway is close to a statement of principle. Walkers navigate by map and terrain and can go for days without meeting anyone. The reward for that austerity is what survives here: this is one of the last Norwegian strongholds of the Arctic fox, with more than twenty known den sites, and the wolverine is the commonest of its large predators. Lesser white-fronted geese, among the most threatened birds in Europe, use the wetlands.

The rock underfoot is acidic — granite and gneiss, weathering into enormous fields of loose boulders that make walking slow and ankle-turning. Only in a central depression does limestone appear, and where it does the vegetation abruptly improves, feeding better pasture. Sami herders have read those differences for generations. That knowledge came under pressure from 1827 onward, when Norwegian and Swedish settlers began moving into the valleys below and the grazing grounds became contested ground rather than simply grazing grounds. The herding did not stop. Every part of Børgefjell is still used as reindeer pasture, and the animals a walker sees at Ranseren in July are not wild — they belong to families who have been bringing them up here since long before anyone drew a line across the lake.

Nothing grows tall at this altitude. The shoreline is heath, rock and low willow, the horizon is unbroken, and the light in the weeks around midsummer never entirely leaves. Ice locks the lake for most of the year and the melt comes late, which is one reason the Stekenjokk road ten kilometres to the southeast stays shut until June. Weather arrives without much warning across ground that offers it no resistance. Come in August and Ranseren is a placid blue line between brown fells, so quiet it seems unvisited. Come in February and the same place is a white trough in a landscape with no reference points at all.